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====Home-Made Supercapacitors from Dead PC Batteries====

This page reports the wonderful citizen science R&D workshop we had at FoAM with my dear friend [[http://www.zprod.org|Paul Granjon]], a world-reknown artist specialized in human-machine co-evolution and [[http://vimeo.com/30187028|participatory upcycling workshops]].

During three day, we tried to upcycle dead PC batteries into working supercapacitors, originally to feed a self-watering system on [[michka/know-hows/bioproductive_balcony|FoAM's bioproductive balcony]].

We ended up being deeply involved with our upcycled supercapacitors manufacturing research and did not proceed to build the rest of the self-watering system. We also ended up having no functional supercapacitor made at the end of our four-days workshop, but  we still obtained some interesting results.

===Best design===

Our best design was very simple. It was a sandwich design, which means that it was just a stack of dry material layers we taped all together. It contained three layers:

   * An insulating material (plastic film) layer from a dead Toshiba battery - given away by [[http://hackerspace.be/|Hackerspace Brussels]], covered with graphene, a black powdery (or sometimes flaky) material
   * A cleaned up insulating material layer from the same dead Toshiba battery
   * A copper layer from the same dead Toshiba battery

This design had the following characteristics:
   * It charged instantaneously - no change on current value was visible on the power source when charging.
   * It displayed a quite stable 0.5 V after charging. FIY, our design had a surface area of approximately 20x5 cm2.
   * When we put four in series, we could bleakly light up a small red LED, showing that there was some charge but not that much.

These characteristics are not outstanding, but still interesting for a 100 % upcycled design.

===How to build the best design ?===

==Step 1 - Find at least one dead computer battery==

We ended up opening three of them:
   * One Apple Macbook Pro 15' battery
   * One Toshiba battery
   * Another Toshiba battery, made of Panasonic round batteries

To open them, use a hacksaw and/or a cutter, and make sure that you are not damaging the internal material. All three designs where made of more or less round rolls of:
   * A lithium layer
   * An insulating material layer
   * A copper layer
   * Intercalated layers of graphene between each couple of these three.

The Toshiba-non-Panasonic battery ended up being the easiest to manipulate. Graphene was easy to clean up from copper & insulating layers, whereas the Apple battery graphene was a nightmare to remove. Robert Murray Smith advises to let it dry for as long as possible before trying to remove it. Ease of manipulation varies with battery design & the kind of damage it overcame, which explains why you may want to start with several dead batteries to go through the process with the easiest to manipulate.

This step of the process is, in my opinion, the most hazardous. If the battery is still a little bit charged, you will end up with heat and sparks. Gloves could be useful. Even when it is not, you will have a strange smell coming out: this is the electrolyte evaporating. As we do not really know what the electrolyte is made of, it may be smart to wear a mask.

==Step 2 - Clean up the graphene from the copper layers & some insulating layers==

Scrap with your nails or whatever soft tools which will not make holes in the plastic or copper layer.

==Step 3 - Assemble the layers==

   * Put the layer of insulating material coated with graphene at the bottom, with the graphene-coated side facing you.
   * Tape a layer of cleaned-up insulating material on top of this one.
   * Tape a layer of cleaned-up copper on top of the second one, making sure to avoid any copper to graphene contact.

==Step 4 - Measure the initial voltage==

Measure the voltage between the copper layer and the graphene layer. There was an initial voltage every time we assembled such a sandwich. This step allows you to see what the polarity of the design is and charge it adequately. Our negative pole was the graphene layer.

==Step 5 - Charge it==

Put the + of the power source on your + pole, and - on -. Check the current flow on your power source screen. We used small voltage to charge, from 1 V to 5 V. Start small.

==Step 6 - Measure the charge==

Once the current is back to 0 A and stable, measure the voltage between the copper layer and the graphene layer.

====Information Sources====

   * [[https://www.youtube.com/user/RobertMurraySmith|Robert Murray Smith's Youtube Channel]]
   * [[https://www.youtube.com/watch?v=SWHpc53759c|neatpete45 video of home-made supercapacitor]]
   * Robert Murray Smith - Supercapacitor 101 - A home Inventor's Handbook (ebook)